The invention relates more particularly to a circuit breaker in which a large current flows (several thousand amps). Circuit breakers of this type are to be found in power stations at the outlet of an alternator and upstream from a tension-raising transformer.
In circuit breakers of this type, the permanent moving contact through which the permanent current flows is generally a copper tube of relatively high mass which is driven at very high speed together with the arcing contact when breaking the circuit. The drive energy required for this operation is large since it is proportional to the product of the mass of the moving equipment multiplied by the square of the speed at which said equipment is displaced. All manufacturers seek to reduce this drive energy since large drive energy penalizes the cost of controlling the circuit-breaking apparatus.
A first aim of the invention is to provide a circuit breaker in which the mass of the moving equipment is reduced, thereby obtaining a corresponding reduction in the drive energy required for a circuit breaking operation.
In known circuit breakers, the permanent current passes through sliding contacts; these contacts must be carefully made and this is reflected in the cost of the apparatus.
Another object of the invention is to provide a circuit breaker in which the permanent current does not flow through sliding contacts, thereby reducing the cost of the apparatus.